Nanophotonic boost of intermolecular energy transfer

We propose a scheme for efficient long-range energy transfer between two distant light emitters separated by more than one wavelength of light, i.e. much beyond the classical Forster radius. A hybrid nanoantenna-waveguide system mediates the transmission of energy, showing enhancements up to 10^8 as compared to vacuum. Our model shows how energy transfer in nanostructured media can be boosted, beyond the simple donor Purcell enhancement, and in particular for large donor-acceptor separations. The scheme we propose connects realistic emitters and could lead to practical on-chip implementations.Comment: 9 pages, 4 figure

Nanoscale mapping and control of antenna-coupling strength for bright single photon sources

Cavity QED is the art of enhancing light-matter interaction of photon emitters in cavities, with opportunities for sensing, quantum information and energy capture technologies. To boost emitter-cavity interaction, i.e. coupling strength , ultrahigh quality cavities have been concocted yielding photon trapping times of µs to ms. However, such high-Q cavities give poor photon output, hindering applications. To preserve high photon output it is advantageous to strive for highly localised electric fields in radiatively lossy cavities. Nanophotonic antennas are ideal candidates combining low-Q factors with deeply localised mode volumes, allowing large , provided the emitter is positioned exactly right inside the nanoscale mode volume. Here, with nanometre resolution, we map and tune the coupling strength between a dipole nanoantenna-cavity and a single molecule, obtaining a coupling rate of max ~ 200 GHz. Together with accelerated single photon output, this provides ideal conditions for fast and pure non-classical single photon emission with brightness exceeding 10E9 photons/sec. Clearly, nanoantennas acting as “bad” cavities offer an optimal regime for strong coupling , to deliver bright on-demand and ultrafast single photon nanosources for quantum technologies.Peer ReviewedPostprint (author's final draft

Descoberta da jazida da Idade do bronze na Tapada da Ajuda

Separata de "Setúbal Arqueológica". Vol. VI-VII, de 1980-81Un «hameau» pré-historique, localisé dans l'aire urbaine de Lisbonne (Tapada da Ajuda) est étudié. Du point de vue géologique et géomorphologique, il est situé sur un versant du Complexe Basaltique de Lisbonne (5ième coulée lavique), de déclive doux et sans défenses naturelles. Parmi les industries recueillies, presque exclusivement à la surface, on peut remarquer l'abondance d'élèments de faucille, sur éclats, en silex (134 exemplaires), quartzite (1 exemplaire) et calcédoine (1 exemplaire), associés à d'autre matériel lithique dont la chronologie fût impossible d'être précisée, vu l'inexistence d'indications stratigraphiques, et d'une abondante céramique e l'Âge du Bronze, dont une partie est de fabrication locale (la présence de mineraux ferromagnésiens dans les pâtes en est témoin). La réalisation d'un talu d'excavation destiné à un terrassement (qui a détruit une partie importante de la station), a permi l'observation d'une coupe ou se concentraient des résidus de cuisine, en particulier de la faune malacologique (surtout Ostrea edule). Des éclats résiduels y ont été recueillis, et aussi un racloir lateral denticulé, deux élèments de faucille sur éclats et des morceaux céramiques typologiquement caraetéristiques du Bronze final. Une analyse camparative des objects étudiés a permit de conclure sur l'exclusivité des élèments de faucille sur éclats en stations de l'Âge du Bronze, au contraire des époques antérieures, où ces élèments étaient surtout façonnés sur lâmes. La rareté des faucilles en bronze (dont on a récemment inventarié seulement 19 exemplaires pour le Portugal), à une époque si tardive de l'Âge du Bronze, peut done s'expliquer par l'efficacité de celles de sílex, très abondants, surtout dans les «habitats-hameaux» de la Péninsule de Lisbonne. Ce modèle d'organisation sociale, qui correspond une à dispersion du peuplement semble caractériser, à cette époque, la fertile région que nous venons de mentioner et pourrait done correspondre à une soeiété au pouvoir centralisé, administrant tout une région, semblablé à ceIui preconisé pour le Bas Alentejo, à la même époque (C. Tavares da Silva e J. Soares, 1978).info:eu-repo/semantics/publishedVersio

Effect of Chemical Pretreatments on the Physical Properties of Kiwi

In this work the effect of pre-treatments on the physical properties of fresh kiwi was studied. For that, a set of tests using chemical pretreatments was used, in which the samples were subjected to aqueous solutions of ascorbic acid and potassium metabisulfite at concentrations of 0.25% and 1% (w/v) for periods of 30 and 60 minutes, in order to understand the implications of the treatments in the color and texture of the kiwi as compared to its original properties. The results showed that the kiwi treated with ascorbic acid changed its color very intensively when compared to the fresh product, and this trend was intensified after storage. Contrarily, when potassium metabisulfite was used, the changes in color were quite negligible right after the treatment and even lower after the storage period of 6 days under refrigeration. After the treatments with both solutions, the kiwi texture was drastically changed, diminishing hardness considerably and increasing elasticity for all treatments. The same could be observed after six days of refrigeration

Anderson Localization Of Composite Excitations In Disordered Optomechanical Arrays

Optomechanical (OMA) arrays are a promising future platform for studies of transport, many-body dynamics, quantum control and topological effects in systems of coupled photon and phonon modes. We introduce disordered OMA arrays, focusing on features of Anderson localization of hybrid photon-phonon excitations. It turns out that these represent a unique disordered system, where basic parameters can be easily controlled by varying the frequency and the amplitude of an external laser field. We show that the two-species setting leads to a non-trivial frequency dependence of the localization length for intermediate laser intensities. This could serve as a convincing evidence of localization in a non-equilibrium dissipative situation. © 2017 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.19

Artefact, Participant and Interaction in Auditory Experiences

Presented at the 27th International Conference on Auditory Display (ICAD 2022) 24-27 June 2022, Virtual conference.The act of sound perception and its subjective dimensions, from physical to psychoacoustics, from semantic to affective, carry an inherent challenge for the conception and evaluation of every audio-based artefact. Starting from a previous framework of evaluation approaches, we seek to deconstruct the configuring elements of these processes, searching for theoretical foundations informing Sound Design and possible applications for Auditory Displays. This work is a first step into identifying a body of knowledge on the listener’s experience, how the act of listening takes place and how the sequence of listening actions can evolve as forms of dialogue, creating dialogical spaces for making sense of auditory information. With this work, practitioners can gain new insights into how existing techniques for creating auditory artefacts can be configured and transformed into new, alternative approaches